A common farming task is the application of material, such as seeds, fertilizer or pesticide, to a field. The material is stored in a tank or bin on a spray truck or tractor and dispensed over the field at a certain rate. A particular number of seeds or weight of fertilizer may be applied per acre, for example. Usually the amount of material carried by a farm vehicle is not exactly right to cover a farm field, however. There may be too much material resulting in some left over at the end of the job, or there may not be enough material and it runs out before the job is finished.
Running out of material early is clearly not desirable, but having material left over is also problematic. Materials often have limited lifetime and can't be stored for future use. Disposing of excess can be expensive and inconvenient. Furthermore farmers do not like to waste seeds, fertilizer, etc. They would rather use up the material in the field.
Analogous situations arise when harvesting except that material is collected from a field rather than dispensed over it. It is undesirable if a harvester reaches its maximum holding capacity at an inconvenient point. Farmers may prefer to unload a harvester near the edge of a field rather than in the middle, for example.
Presently farmers solve problems of running out or having too much by guesswork and feel. As a vehicle nears the last few rows a field an operator applies a little more or less material to use up or stretch out the amount available. This is done by adjusting flow rates, seed rates or other parameters. Another approach for “running out” problems is traversing part of a field a second time with a new load. This is frowned upon when crops are growing, however, as multiple passes tend to damage plants.
When a farmer sees that a storage bin on a harvester is getting full he must decide whether to keep going and risk reaching a capacity limit at an inconvenient point, or stop early and risk reduced efficiency if it turns out it would have been possible to harvest additional rows. Besides the inherent inaccuracy of guesswork, trying to predict application or harvesting endpoints is an unnecessary distraction for a vehicle operator that has many other tasks demanding his attention.
What are needed are systems and methods for managing agricultural application and harvesting rates. Farmers should not have to rely on, and be distracted by, guesswork to manage spray rates, position nurse tanks, plan for unloading stops, etc.